Wasted Food Emits Massive Amounts of Greenhouse Gases

When asked to name the causes of climate change, few would imagine that the food we throw out every day is one of the biggest culprits. But it is.

A new report from the United Nations' Food and Agriculture Organization shows that not only is about one-third of the food produced for human consumption every year lost or wasted – it's also the world's third-biggest emitter of greenhouse gases, behind only the United States and China.

As it rots, wasted food adds the equivalent of more than 3.6 billion tons of carbon dioxide into the atmosphere, the report estimates, primarily through the release of methane, a heat-trapping greenhouse gas that's more than 20 times more potent than carbon dioxide.

Most food waste in wealthy, Western countries occurs largely because we throw out leftovers and unused ingredients, the environmental website Grist.org notes, or when the food farmers grow doesn't meet retailers' "cosmetic expectations" (like misshapen fruit), ensuring it never makes it to the supermarket in the first place.

Beyond its environmental impacts – which include massive volumes of water and land used to produce food that never gets eaten, estimated by the FAO at about 30 percent of the world's agricultural land area – food waste extracts a huge economic toll as well.

In 2007, the FAO estimates that the world produced about $750 billion worth of food that was never consumed, an amount equal to an entire year's gross domestic product for countries the size of Turkey and Switzerland in 2011.

Reducing the amount of food wasted each year could have a major impact on the release of greenhouse gases, one of the main drivers of global warming and climate change. As the online magazine Next Generation Food shows in an infographic titled "The Big Food Wasters," stopping food waste would be the equivalent of taking one of every four cars off the road.

Food waste facts

Roughly one-third of the food produced around the world for human consumption every year – about 1.4 billion tons – is lost or wasted.

Food loss and waste also amount to a major squandering of resources, including water, land, energy, labor and capital and the needless production of greenhouse gas emissions, which contribute to global warming and climate change.

In the U.S., 30 percent of all food – worth more than $48 billion – is thrown away each year. It is estimated that about half the water used to produce this food also goes to waste, because agriculture is the largest human use of water.

Organic waste (which includes food) makes up the second-highest component of landfills, one of the largest source of methane emissions.